Method and apparatus for spinal facet joint fusion using irregularly shaped cortical bone implants

ABSTRACT

A method and apparatus for spinal fusion at the facet joint using an irregularly shaped implant where the orientation of the implant can be preselected before implantation.

CROSS-REFERENCE TO RELATED APPLICATIONS

Priority of U.S. Provisional Patent Application Ser. No. 60/988,911,filed Nov. 19, 2007, incorporated herein by reference, is herebyclaimed.

BACKGROUND

The spine includes a row of 26 bones in the back and allows a person tostand up straight and bend over. The spine also protects a person'sspinal cord from being hurt. In people with spinal stenosis, the spineis narrowed in one or more of three parts: (1) the space at the centerof the spine; (2) the canals where nerves branch out from the spine; and(3) the space between vertebrae (the bones of the spine). This narrowingputs pressure on the spinal cord and nerves and can cause pain.

Facet joints are small stabilizing joints located between and behindadjacent vertebrae of the spine. Facet joints restrict excessive motion,twisting, or toppling over of the vertebrae relative to one another.

It is believed that facet joint disorders (such as facet jointdeterioration and disease) are among the most common of all therecurrent, disabling low back problems that have serious symptoms anddisability. In many cases where facet joints are excessively damaged,preventing movement to manage pain is preferred to attempts to repairthe joints such as by replacements.

Facet joint fusion can be a stand alone treatment system or a supplementto other fusion systems by fixing facet joints and reducing stress onthe primary fusion system compared to when the facet joints are allowedto freely move relative to one another.

It is believed that many conventionally used fusion systems failprematurely because of mechanical failure of one or more facet joints,and degenerative joint disease.

Treatment of degenerative disc disease, degenerative joint disease,osteoarthritis and other indications of spinal problems typically haveincluded spinal fusion using pedicle and other screw based fixationsystems, such as trans-facet compression screws (i.e., perpendicular tothe facet plane), and lumbar facet interference screw systems. Facetdowels have also been used, but have been found in many cases to extrudefrom the insertion location, failing to promote fusion.

Caused by aging, spinal stenosis is most common in men and women over 50years old. Younger people who were born with a narrow spinal canal orwho hurt their spines may also get spinal stenosis. Changes that occurin the spine as people get older are the most common cause of spinalstenosis such as: (a) the bands of tissue that support the spine may getthick and hard; (b) bones and joints may get bigger; and (c) surfaces ofthe bones may bulge out, which are called bone spurs. In some casesarthritis, a degenerative condition, can cause spinal stenosis. Twoforms of arthritis that may affect the spine are: (a) osteoarthritis and(b) rheumatoid arthritis.

Osteoarthritis is the most common form of arthritis and most oftenoccurs in middle-aged and older people. It may involve many joints inthe body where it wears away the tough tissue (cartilage) that keeps thejoints in place and can cause bone spurs and problems with joints.

Rheumatoid Arthritis affects most people at a younger age thanosteoarthritis. It causes the soft tissues of the joints to swell andcan affect internal organs and systems. However, it is not a commoncause of spinal stenosis but can cause severe damage, especially tojoints.

Some people are born with conditions that cause spinal stenosis. Forinstance, some people are born with a small spinal canal. Others areborn with a curved spine (scoliosis). Other causes of spinal stenosisare: tumors of the spine; injuries; Paget's disease (a disease thataffects the bones); too much fluoride in the body; and calcium depositson the ligaments that run along the spine.

In many cases there may be no symptoms of spinal stenosis, or symptomsmay appear slowly and get worse over time. Signs of spinal stenosisinclude: pain in the neck or back; numbness, weakness, cramping, or painin the arms or legs; pain going down the leg; and foot problems.

One type of spinal stenosis, cauda equine syndrome, is very serious.This type occurs when there is pressure on nerves in the lower back.Symptoms may include: loss of control of the bowel or bladder; problemshaving sex; and pain, weakness, or loss of feeling in one or both legs.

Because spinal stenosis has many causes and symptoms, treatment may berequired from doctors who specialize in certain aspects of thecondition. Health care providers can include: rheumatologists (doctorswho treat arthritis and related disorders); neurologists andneurosurgeons (doctors who treat diseases of the nervous system);orthopedic surgeons (doctors who treat problems with the bones, joints,and ligaments); and physical therapists.

As people age the amount of adverse spinal conditions tend to increase.For example, increases in spinal stenosis, such as central canal andlateral stenosis, along with the thickening of the bones making up thespinal column and facet arthropathy are expected. Spinal stenosistypically includes a reduction in the available space for the passage ofblood vessels and nerves which can impinge on these. Pain associatedwith such stenosis can be relieved by surgery. However, it is desirableto reduce the circumstances for which major surgeries are required toaddress stenosis.

The facet joints comprise part of the stability and mobility system ofthe human spine. The two facet joints compromise part of the posteriorelements of the spine. They serve to limit translation of the spine butallow motion. There are nerves that service the capsule of the facetjoints. The joints are a source of pain in many patients. Since theyallow motion that can allow pain, fixation via stabilization can havebenefits. Permanent fixation methods include metallic screws, wiring orbone grafting. Many techniques are destructive and can have adverseeffects. Metallic implants can be rejected, broken, loosened, orimproperly placed.

Facet fusion via the method and apparatus of the present invention canbe accomplished with minimum additional risk or problems. Accordingly,it is desired to develop procedures and implants for surgicallyaddressing stenosis through minimally invasive procedures, andpreferably such surgical procedures can be performed on an outpatientbasis. Spinal stenosis is an extremely common cause of problems acrossthe world. Many patients undergo decompression surgery to treat thestricture of the spinal canal (i.e. stenosis). This surgery requiresremoval of bone and ligaments. This process can also be a common sourceof back pain. The term “glacial iatrogenic instability” applies to thisscenario. Many patients undergoing a laminectomy procedure havepre-existing pain in their spine.

SUMMARY

The method and apparatus of the present invention is greatly useful forthis subset of patients. The facet joints can easily be exposed duringthis type of surgery. The technique is incredibly simple when the jointis exposed.

In one embodiment a T-handled trocar is docked on the joint. A “stamp”which can be disposable can be placed in an inserter device. Oncesecure, this device is run down the trocar until it stops. In manycircumstances the cortical bone, cartilage endplate and synovium willexit with the stamp. If it does not, a surgeon removes the stamp andplaces the graft holder on the inserter and replace down the trocar. Thegraft holder is closed to lock the debris in the graft holder forremoval. The graft will then be placed in the graft holder and impactedwhen flush via a press fit in the track.

The novel design of the present invention is an improvement over otherfacet fusion devices. This device of the present invention will removethe cartilage, synovium and cortical bone. This allows the graft directaccess to the cancellous bone on both sides of the facet joint tofacilitate fusion. The design of the present invention provides acarpenter's shape that is more stable and will resist motion to thus aidin immediate back pain relief.

Many patients with spinal stenosis also have a condition calledspondylolisthesis. This is slippage of one vertebral body on the oneadjacent to it. Many of these patients will require decompression. Theconcern for this subset of patients after decompression is glacialinstability. Facet fusion offers these patients stability without thenecessity of spinal instrumentation. This thereby also allows for areduction of additional surgery as this hardware often has to be removedat a later date.

Many patients complain of mechanical and facet driven back pain. Thefacet fusion procedure allows for mini-open versus percutaneous fusionprocedure that is much less invasive than standard fusion surgery. Thisgraft can be implanted via the standard instruments and fluoroscopicguidance. This gives patients an opportunity for pain relief withoutmetallic implants and decreases operative time and blood loss.

Another subset of patients who benefit from the technique of the presentinvention are patients with recurrent disc herniation. The presentinvention allows for a less invasive and rapid stabilization method andshould decrease the risk of additional disc herniation.

The graft and method of the present invention can also be used inconcert with standard fusion techniques. By fixating the facet joints,this will augment standard instrumented and non-instrumented fusion.

The graft of the present invention can be machined cortical allograft.It serves to lock the two surfaces of the facet joint together in a waythat decreases motion immediately and thereby decreases back pain. Thebone will then go on to arthrodesis.

In one embodiment the instrument set of the present invention can becomprised of a T-handled trocar, an inserter, a disposable stamp orcutter, and a disposable graft holder. The graft will be sterile and canbe packaged as a single unit. In one embodiment the device can be usedin the thoracic and lumbar spine. In one embodiment bilateral grafts canprovide optimum efficiency. In one embodiment only a single side can begrafted.

In one embodiment the method and apparatus benefits the patient,hospital, and surgeon. It offers a less invasive option for treatment ofback pain. It is quick, simple and has immediate efficacy. Complicationfrom implantation should be nominal. The cost savings to the hospitalsis tremendous when compared to traditional methods.

One embodiment provides a minimally invasive method and apparatus forspinal facet joint fusion using irregularly shaped bone implants or bonescrews which are positioned and then implanted in the direction of thefacet plane.

One embodiment includes using an allograft such as donated human cadaverbone recovered from a donor's leg, and processed by a tissue bank.Preferably, it is recovered from the hard, or cortical, part of thelargest leg bone, or femur. One embodiment includes using bone fromanimal bone. One embodiment includes using a material which isbiodegradable in the body.

One embodiment includes minimally invasive spine surgery such as anarthroscopic type portal or open facet joint fusion surgicalinstrumentation for insertion of either pre-made, pre-shaped syntheticirregularly shaped bone implant or graft, or harvested and compactediliac crest grafts, autologous or cadaveric allografts which areirregularly shaped.

In one embodiment the method and apparatus can be used on one or more ofthe forty-eight facet joints located on the spine (i.e., C1-C2 throughL5-S1).

The use of an irregularly pre-shaped, harvested or synthetic bone as astructural fixation for facet joint fusion has the advantage of usingbone instead of metal allowing for natural bone ingrowth and a stronger,permanent fusion; and (2) the natural or synthetic graft cannot work itsway loose over time, a concern with screw type fixation.

One embodiment includes the use of a minimum invasive or an arthroscopictype portal for stand-alone procedures.

One embodiment includes use of an irregularly shaped bone implant as anadjunct to other fusion techniques.

One embodiment includes the use of a shaped bone implant having aplurality of arms and valleys (such as in the shape of an “X” or “cross”with rounded valleys and edges).

In one embodiment, the method and apparatus includes: (a) providing apositioning selector that allows the visual selection of the relativerotational angular and Cartesian coordinate position of the implant tobe placed relative to the facet joint along the length of a facet jointor in the plane of the facet joint (i.e., taking materials from both thesuperior and inferior portions of the facet joint); (b) placing a guidetool which maintains such selected rotational angular position alongwith the selected Cartesian coordinate position; (c) using a cuttingtool which makes an opening in the spine corresponding to the chosenrelative position; and (d) inserting an irregularly shaped bone implantin the bone where the irregularly shaped bone implant also maintains thecorresponding rotational angular position.

One embodiment includes the use of a positioning selector for allowingthe visual selection of the relative rotational angular and Cartesianposition of the implant to be implanted.

One embodiment includes the use of a guide tool for maintaining theselected relative rotational angular and Cartesian position during theprocess of cutting the opening for the implant and then implanting theimplant.

One embodiment includes the use of a guide tool for guiding a cutterduring the process of forming the graft opening or bore, and forstopping the cutter when the graft opening or bore reaches apredetermined depth.

In one embodiment the guide tool and cutter include a plurality ofindicia which visually indicate the extent depth of the opening for theimplant.

In one embodiment the cutter includes a tapered portion so that theaverage cross sectional area of the opening or bore decreases as thedepth increases. In one embodiment the graft also has a tapered portiontracks or follows the tapered portion of the opening or bore.

One embodiment includes the use of an implant insertion tool which holdsthe implant and maintains a relative rotational angular position betweenthe implant and the guide tool so that the selected relative rotationalangular position selected for the implant is maintained and so that theimplant can be inserted into the opening of bore made by the cutter.

One embodiment includes the use of an impacting tool or driver which canbe used to separate the implant from the implant insertion tool. In oneembodiment the relative angular position between the impacting tool andthe implant is not constrained and can change.

One embodiment includes the use of an insertion guide and stop forlimiting the depth of the driver during the process of inserting thebone graft into the opening or bore, and for stopping the bone implantwhen the depth of implant reaches a predetermined depth.

One embodiment includes one instrument for guiding and stopping for eachof the above specified activities.

One embodiment provides a method and apparatus for relieving pain byrelieving the pressure and restrictions on the blood vessels and nervesassociated with the spine. This can be accomplished using a method andapparatus for spinal facet joint fusion using irregularly shaped boneimplants or grafts which fuse two or more vertebrae in order toalleviate the problems caused by spinal stenosis, facet arthropathy, andsimilar conditions.

One embodiment provides a method and apparatus for spinal facet jointfusion using irregularly shaped bone implants or grafts comprising aplurality of facet joint implants or grafts positioned between the facetjoints between the upper portion of the facet joint and the lowerportion of the facet joint of a first vertebra and a second vertebra.

One embodiment provides a method and apparatus for spinal facet jointfusion using irregularly shaped bone implants or grafts for relievingpain due to conditions such as spinal stenosis and facet arthropathy.The method includes the steps of accessing adjacent first and secondvertebrae of the spinal column and using irregularly shaped boneimplants or grafts to fuse the facet joints between these vertebrae torelieve pain.

One embodiment includes a method and apparatus for spinal facet jointfusion using irregularly shaped bone implants or grafts to be able toaccommodate the anatomical structure of multiple vertebrae and differentsizes of facet joints for vertebrae.

One embodiment includes an irregularly shaped allograft cortical bonescrew and matching die and tap system to achieve a secure fit forposterior fixation and permanent fusion.

One embodiment includes a minimally invasive surgical technique usingconventionally available dilating or retraction systems or open surgerywith a cutting guide and driving tool for cutting the opening for theimplant or graft into the facet joint to achieve fusion. Minimallyinvasive (or minimally destructive) surgical techniques use smallincisions and techniques to spread muscle and tissue rather than cuttingthrough these when reaching the area to be surgically treated. Thesetechniques result in less blood loss, risk, and post-operative pain,less physical therapy, and rehabilitation; allowing patients to recovermore quickly.

One embodiment includes the implant being inserted in a non-traumaticfashion, and avoiding the risks of neural contusion, and rupture of theimplant during the implantation process.

One embodiment includes an implant which has physical characteristicssimilar to the bone in which it is being implanted to facilitategrafting and minimal stresses on the fused vertebrae facets.

One embodiment uses harvested human bone, or cadaveric allograft.

One embodiment provides temporary fixation while the body's naturalhealing process permanently fuses the joint together by growing naturalbone into the threaded member.

One embodiment includes a method and apparatus for facet fusion withreduced hospital (or outpatient time) and faster recovery time based onthe methods minimally invasive properties.

One embodiment includes the cutting of an irregularly shaped opening inthe plane of the facet joint of a specific level between superior andinferior facet surfaces. This bore is die cut such as by using a dietool. A matching irregularly shaped implant (matching shape to the cutand being of a cortical bone implant) is then placed (e.g., pushed) intothe graft opening completing the fusion of the facet joint. Over timethe implant will fuse together with the superior and inferior facetsurfaces.

One embodiment includes the tapping or cutting of another opening in theplane of the second facet joint of the specified level between superiorand inferior facet surfaces where a second irregularly shaped implant(cortical bone implant or screw) is then placed (e.g., pushed) into thissecond opening completing the fusion of this second facet joint. Theirregular shape of the implants increase the contact area between thespine and the implant (thus decreasing the overall fusion time), andalso resists differential rotation between the upper and lower portionsof the facet joint. The irregular shape is also believed to reduce therisk that the implant will extrude out of the fusion site.

In one embodiment two irregularly shaped implants for each level offusion are used.

In one embodiment one of both of the openings bores in the facet jointsof a specified level are of differing irregular shapes. In oneembodiment both are the same irregular shape.

In one embodiment stops and/or guides are provided on the implanttooling to ensure that the implant will not penetrate the foramen.

In one embodiment the implants for a specified level are stand alonefusion devices. These can be used to treat adjacent segment disease,degenerative joint disease of the facets or asteoarthritis.

In one embodiment the implants for a specified level are used tosupplement posterior fusion techniques (such as cages).

In one embodiment the implants for a specified level are used tosupplement anterior fusion techniques.

In one embodiment facet joint fusion can be used for decompression andlaminectomy instead of another fusion system.

In one embodiment facet joint fusion can be used to supplement posteriorfusion systems when a corpectomy has been performed.

In one embodiment facet joint fusion can be used in connection withinstrumentation to correct scoliosis.

In one embodiment average surgical times for each level of fusion can beless than 60 minutes, less than 45 minutes, less than 30 minutes.

In one embodiment the method and apparatus can be used for C1-C2 throughL5-S1.

In one embodiment the angle of approach of the cutting tool is posteriorstraight into the facet joint.

In one embodiment, at a specified level, the opening or bore of thefirst facet joint passes through the first facet joint and the bore ofthe second facet joint passes through the second facet joint.

In one embodiment, at a specified level, the angle of the opening orbore of the first facet joint is the same as the angle of the opening orbore of the second facet joint.

In one embodiment, at a specified level, the angle of the opening orbore of the first facet joint is different from the angle of the openingor bore of the second facet joint.

In one embodiment the opening or bore is made in the central portion ofthe facet joint. In one embodiment the opening or bore is shifted oversuch as ⅔ to one side and ⅓ to the other side.

In one embodiment the angle of approach does not fully comprise thejoint and other instrumented options are available.

In one embodiment one or more CT scans can be used to determine boredepth to be stamped or prepared. In one embodiment bore depth can beless than or equal to 50 percent of the smallest facet surface area.

In one embodiment less than or equal to fifty percent of the facet jointis consumed in making the bore.

In one embodiment the method and apparatus can be used in place of afacet screw system.

In one embodiment the method and apparatus can be used to augment ananterior spinal fusion technique.

In one embodiment the method and apparatus can be used to augment aposterior spinal fusion technique.

In one embodiment the method and apparatus can be used as a stand aloneposterior fusion.

One embodiment comprises the following steps:

(a) localize the facet joint either by direct visualization during opensurgery or indirectly by fluoroscopy;

(b) remove the posterior capsule as well as any significant osteophytesor bone spurs (which can get back down to the original joint levelwithout compromising the native bone);

(c) if necessary, clear the facet joint of any remaining cartilage ofdebris, such as with an arthroscopic rasp, or one millimeter burr and inline with the facet joint angle (i.e., in the same plane);

(d) place a positioning selector over the facet joint to select theposition of the implant (relative rotation and Cartesian);

(e) place the guide tool over the positioning selector;

(f) remove the positioning selector;

(g) insert the cutting tool into the guide tool to cut an implantopening in the facet joint (such as in the plane of the facet joint);

(h) remove the cutting tool;

(i) insert plug removal tool (if needed);

(j) remove plug (or pieces of plug)

(k) insert an implant and implant holding tool into the guide tool untilthe implant at least partially enters the opening in the facet joint;

(l) insert an impaction tool into the guide tool to further insert theimplant into the opening of the facet joint and detach the implant fromthe guide tool and implant holding tool; and

(m) repeat the above steps for the second facet joint at the same level;

In one embodiment the irregularly shaped implants restrict the spinalfacet joint surfaces at a specified level from moving relative to eachother, and thereby allow the surfaces to graft together over time forpermanent fusion.

Various embodiments of the method and apparatus can be used to fusefacet joints thereby alleviating impingements and/or restrictions onvessels and nerves associated therewith, and reducing pain caused bysuch restrictions.

In one embodiment creation and of a surgically cut bore or opening in afacet joint is accomplished without creating tiny bone fragments (suchas that caused by drilling) which can migrate into other parts of apatient's body.

In one embodiment a stamp or cutter can be used to cut through sonovialand/or cartilage materials along with the bone in creating a surgicallycut bore or opening in a facet joint for an insert, implant, or plug.

In one embodiment a stamp or cutter can be used to cut through sonovialand/or cartilage materials along with the bone in creating a surgicallycut bore or opening in a facet joint for an insert, implant, or plugwherein no substantial amount of sonovial and/or cartilage material ismixed in and/or remains in the bore or opening thereby enabling purebone to bone contact between the insert, implant, or plug and thesurgically cut opening or bore thereby increasing the fusion between theportions of the vertebrae forming the facet joint and the insert,implant, or plug and speeding up the patient's recovery from the fusion.

In one embodiment a press fit is made between the surgically cut openingor bore and the insert, implant, or plug placed or fit into the openingor bore.

In one embodiment various advantages exist over conventional systems.

One embodiment includes a grafting system using a cutter to remove thesynovium, cartilage and cortical bone at the interface of the facetjoint. This allows the medullary bone to be exposed directly to theallograft.

In conventional systems drilling tend to push debris (cartilage andsynovium) into the medullary channels (trabeculae). The basic tenet ofmaximum surface area of graft to host bone contact is achieved in thisfashion. Currently available systems use drills to ream out a tract forgraft insertion, thereby plugging many channels of viable boney surfacearea for fusion. This process can inhibit the fusion process.

Various embodiments uses unique shapes to avoid graft extrusion andprovide better host bone to graft bone contact. Existing systems utilizeround graft shapes. Due to the forces applied to the joint due to humanmotion in an upright model, many of these grafts can extrude.

In one embodiment is used an hourglass design which places the “ends ofthe hourglass” firmly in the opposite sides of the facet joint. Theleading end of the graft has a taper to allow for slight over sizing ofthe graft to account for shrinkage issues with individual donors. Italso allows for ease of graft insertion during the “press fit” process.

In one embodiment a ridge can be added to the non leading end of thebone graft to engage the joint and add another “buttress” feature toprevent graft extrusion.

In one embodiment the method and apparatus utilizes disposable bonecutters to avoid the risk of disease transmission. Conventionaltechniques use non-disposable drill bits that can, if improperlycleaned, lead to disease or infection transmission.

In one embodiment the method and apparatus requires no motorized powersource, leading to decreased operative time if the power to the drill iscompromised.

In embodiment it is recommended that the facet joint locator instrumentbe used to locate the angle or orientation of the facet joint to promoteproper alignment, and avoid misalignment, of the implant, insert, orplug.

In one embodiment will be included a cannulated version to allow fortrue percutaneous implantation.

While certain novel features of this invention shown and described beloware pointed out in the annexed claims, the invention is not intended tobe limited to the details specified, since a person of ordinary skill inthe relevant art will understand that various omissions, modifications,substitutions and/or changes in the forms and details of the deviceillustrated and in its operation may be made without departing in anyway from the spirit of the present invention. No feature of theinvention is critical or essential unless it is expressly stated asbeing “critical” or “essential.”

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side fragmentary view of a guide tool which can be used inthe method and apparatus;

FIG. 2 is an end view taken along lines 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along lines 3-3 of FIG. 1;

FIG. 4 is a sectional view taken along lines 4-4 of FIG. 1;

FIG. 5 is a top view taken along lines 5-5 of FIG. 1;

FIG. 6 is a side fragmentary view of the preferred embodiment of theapparatus of the present invention showing the cutting tool assembly;

FIG. 7 is a top view taken along lines 7-7 of FIG. 6;

FIG. 8 is an end view taken along lines 8-8 of FIG. 6;

FIG. 9 is an end view taken along lines 9-9 of FIG. 6;

FIG. 10 is a fragmentary view of the preferred embodiment of theapparatus of the present invention showing the cutter;

FIG. 11 is a sectional view taken along lines 11-11 of FIG. 10;

FIG. 12 is an end view taken along lines 12-12 of FIG. 10;

FIG. 13 is a partial perspective view of the preferred embodiment of theapparatus of the present invention showing the cutter;

FIG. 14 is a fragmentary side view of the preferred embodiment of theapparatus of the present invention showing the holder;

FIG. 15 is a perspective exploded view of the preferred embodiment ofthe apparatus of the present invention showing steps in assembling thecutting tool assembly;

FIG. 16 is a partial perspective view of the preferred embodiment of theapparatus of the present invention showing the cutting tool assembly inan assembled condition;

FIG. 17 is a schematic side elevation view of the preferred embodimentof the apparatus of the present invention illustrating placement of theguide tool of a facet joint, and insertion of the cutting tool assemblyinto the guide tool;

FIG. 18 is a schematic side elevation view of the preferred embodimentof the apparatus of the present invention illustrating placement of theguide tool and cutting tool assembly and force being applied to thecutting tool assembly to make an opening or bore in the facet joint;

FIG. 19 is a schematic side elevation view of the preferred embodimentof the apparatus of the present invention at the end of the stepillustrated in FIG. 18, and now illustrating completion of downwardmovement of the cutting tool assembly into the guide tool for making anopening or bore in the facet joint;

FIGS. 20-20A are perspective views of a patient's spine illustrating thefacet joints and placement/location of an implant or graft using themethod of the present invention where the insert, implant, or graftspans the facet joint on the left hand portion of the facet joint andthe right hand portion of the facet joint does not have an implant orgraft;

FIG. 21 is a perspective view of a patient's spine illustrating thefacet joints and placement/location of two implants or grafts using themethod of the present invention where the inserts, implants, or graftsspan their respective facet joints;

FIG. 22 is a side view of the preferred embodiment of the apparatus ofthe present invention showing the tool for holding and inserting insert,implant, or graft;

FIG. 23 is a side view of the preferred embodiment of the apparatus ofthe present invention showing the impaction tool for dislodging theinsert, implant, or graft from the tool of FIG. 22 and into the openingor bore of the facet joint made by a cutting tool;

FIG. 24 is an end view taken along lines 24-24 of FIG. 22;

FIG. 25 is a sectional view taken along lines 25-25 of FIG. 22;

FIG. 26 is a sectional view taken along lines 26-26 of FIG. 22;

FIG. 27 is an end view taken along lines 27-27 of FIG. 22 with stopcollar omitted for clarity;

FIG. 28 is a fragmentary view of the preferred embodiment of theapparatus of the present invention and showing the insert, implant, orgraft;

FIG. 29 is an end view taken along lines 29-29 of FIG. 28;

FIG. 30 is a side view illustrating the insert, implant, or graft;

FIG. 31 is a side view illustrating an alternate embodiment of theinsert, implant, or graft;

FIG. 32 is a perspective view of the insert, implant, or graft shown inFIGS. 28-30;

FIG. 33 is an end view of the insert, implant, or graft of FIGS. 28-30and 32;

FIG. 34A is a perspective view illustrating removal of the cut orstamped out coupon or plug from a cutting tip of a cutting tool wherethe impaction tool of FIG. 23 can be used for pushing out the coupon orplug from the cutting tip;

FIG. 34B is a perspective view illustrating insertion of an insert,implant, or graft into the tool for holding the insert, implant, orgraft;

FIG. 35 is a schematic elevation view of the preferred embodiment of theapparatus of the present invention illustrating the steps of removingthe cutting tool with cut out coupon (shown in FIG. 34A) andsubsequently inserting the insertion tool holding insert, implant, orgraft to be inserted (shown in FIG. 34B) where both the cutting tool andinsertion tool and slide into and out of the guide tool;

FIG. 36 is a schematic side view of the preferred embodiment of theapparatus of the present invention illustrating the insertion tool withinsert, implant, or graft placed in an opening or bore of the facetjoint and the step of using the impaction tool to push the insert,implant, or graft into the patient's spine at the facet joint;

FIG. 37 is a schematic view illustrating placement of two inserts,implants, or grafts in a patient's spine at the facet joints;

FIG. 38 is a partial perspective view of the preferred embodiment of theapparatus of the present invention showing the grabbing tip of the plugor coupon removal tool;

FIG. 39 is an exploded perspective view of the preferred embodiment ofthe apparatus of the present invention indicating the steps ofassembling the various components of the plug or coupon removal tool;

FIG. 40 is a sectional view of the plug or coupon removal tool of FIG.38;

FIG. 41 is a perspective view of a template or gauge that is used withthe plug or coupon removal tool of FIGS. 38-40;

FIG. 42 is a perspective view of an assembled plug or coupon removaltool of FIGS. 38-41;

FIG. 43 is a perspective view of the plug or coupon removal tool ofFIGS. 38-41 illustrating the step of using the gauge or template of FIG.41 to size the grabbing tip of FIG. 38 which grabbing tip can then beused to grab and remove the plug or coupon which had been cut using acutting tool;

FIG. 44 is a perspective view of the remove tool of FIGS. 38-41 showingthe gauge or template being removed from the now sized grabbing tip;

FIG. 45 is an elevation view of the preferred embodiment of theapparatus of the present invention illustrating the step of using plugor coupon removal;

FIG. 46 is an elevation view of the preferred embodiment of theapparatus of the present invention illustrating dislodgement of the plugor coupon from the plug or coupon removal tool;

FIG. 47 is an elevation view of the preferred embodiment of theapparatus of the present invention illustrating plug or coupon removalwhere the grabbing tip of the plug or coupon removal tool is beingplaced of the cut section of the plug or coupon in the facet joint;

FIG. 48 is an elevation view of the preferred embodiment of theapparatus of the present invention illustrating plug or coupon removalwhere the grabbing tip of the plug or coupon removal tool has beenplaced of the cut section of the plug or coupon in the facet joint;

FIG. 49 is an elevation view of the preferred embodiment of theapparatus of the present invention illustrating plug or coupon removalwhere the grabbing tip of the plug or coupon removal tool is beingsqueezed over the cut section of the plug or coupon in the facet joint;

FIG. 50 is an elevation view of the preferred embodiment of theapparatus of the present invention illustrating plug or coupon removalwhere the squeezed grabbing tip of the plug or coupon removal toolpulling out the cut section of the plug or coupon leaving a bore oropening in the spine of the patient around the facet joint;

FIG. 51 is a sectional view of the bore or opening taken along lines51-51 of FIG. 50;

FIG. 52 includes various alternative irregular shapes for the inserts,implants, plugs, or grafts beyond an X or cross shape;

FIG. 53 is a fragmentary side view of an alternate cutting tool whichcan also be used as the plug or coupon removal tool;

FIG. 54 is a side fragmentary view showing an optional handle for usewith the alternate plug or coupon removal tool;

FIG. 55 is a side view showing an alternate cutter for use with thealternate plug or coupon removal tool;

FIG. 56 is a fragmentary perspective view showing the alternate cutterof FIG. 55;

FIG. 57 is a fragmentary side view showing part of the plug or couponremoval tool;

FIG. 58 is a fragmentary side view showing threaded wedging memberportion of the alternate plug or coupon removal tool;

FIG. 59 is an exploded perspective view illustrating the steps ofassembling the alternate plug or coupon removal tool;

FIG. 60 is an exploded elevation view illustrating the step of insertingthe threaded wedging member into the alternate coupon tool after thetool was used to cut the bore or opening in a patient's spine about thefacet joint;

FIG. 61 is side elevation view illustrating the step of turning andscrewing in the threaded wedging member into the cut or stamped plug orcoupon;

FIG. 62 is a partial sectional elevation view showing the alternate plugor coupon removal assembly with the threaded wedging member screwed intothe cut or stamped plug or coupon so that the two pieces of the plug orcoupon are expanded against the walls of the cutting tip;

FIG. 63 is an exploded elevation view showing the alternate plug orcoupon removal assembly being pulled up with the plug or coupon to forma bore or opening in the spine of a patient about the facet joint;

FIG. 64 is a sectional view taken along lines 64-64 of FIG. 62illustrating that preferably the threaded wedging member will threadinto the facet joint and then be between the two portions of the plug orcoupon which causes these pieces to expand against the walls of thecutting tip along with the threads threading into each of the twopieces;

FIG. 65 is a partial sectional elevation view showing the alternate plugor coupon removal assembly being pulled up with the plug or coupon toform a bore or opening in the spine of a patient about the facet joint;

FIG. 66 is a partial perspective view showing an alternate couponremoval tool with an alternate grabbing tip with gripping spurs orburrs;

FIG. 67 is a sectional view taken along lines 67-67 of FIG. 66;

FIG. 68 is a sectional view taken along lines 68-68 of FIG. 67;

FIG. 69 is a side view of a facet joint locator having at least onelongitudinal positioning line;

FIG. 70 is a sectional view of the facet joint locator of FIG. 69 takenalong the lines 70-70 of FIG. 69;

FIG. 71 is a perspective view of the facet joint locator of FIG. 69.

FIG. 72 is a perspective view of a step in the method and apparatus ofone embodiment where the surgeon uses the facet joint locator of FIG. 69to locate the facet joint;

FIG. 73 is a close up perspective view of the facet joint locator showninside the facet joint;

FIG. 74 is a side view of the guide tool being positioned over the facetjoint locator and contacting the spine of a person over the facet joint;

FIG. 75 is a partial perspective view of the guide tool and facet jointlocator where the guide tool has a positioning mark on its handle whichis lined up with the positioning mark of the facet joint locator, andsuch lining up orients subsequent steps of the method and apparatusproperly with respect to the orientation of the opening or bore in thefacet joint to be fused;

FIG. 76 is a perspective view of an insert, implant, plug, or graftbeing placed in one embodiment of the insertion tip of the method andapparatus in which a portion of the insert extends outside of theinsertion tip;

FIG. 77 is a sectional side view of the insertion tip placing theinsert, implant, plug, or graft into the opening or bore previously madearound the facet joint of a person's spine where the orientation of theinsert, implant, plug, or graft is maintained with the opening or borebased on the orientation of the original facet joint locator shown inFIG. 75; and

FIG. 78 is a sectional side view where an insertion rod is used to fullypush the insert, implant, plug, or graft into the opening or bore aboutthe facet joint.

DETAILED DESCRIPTION

“Allograft” is the transfer of tissue between two genetically dissimilarindividuals of the same species but genetically distinct.

“Xenogeneic” denotes individuals or cell types from different speciesand different genotypes, such as tissues from different species that areantigenically dissimilar.

The term “Graft” includes both an Allograft and/or a Xenogeneic unlessspecified otherwise.

FIG. 17 is a perspective view of a portion of a spinal column 1100,along with a guide tool 300 having handle 380 just prior to insertion ofcutting tool assembly 500 of upper and lower vertebrae 1200, 1300. InFIG. 21, two irregularly shaped implants 10, 11 are inserted in two setsof facet joints 1230, 1231. FIGS. 21 and 37 are sectional views of thelower vertebrae 1200, 1300.

Spinal column 1100 includes a plurality of vertebrae (includingvertebrae 1200 and 1300). Spinal column 1100 also includes a spinal cordand nerve roots. In one embodiment the method and apparatus can beimplanted to fuse together the facet joints of two or more sets of upperand lower vertebrae, which fusion can reduce pain caused by nerve rootimpingement or other problems with the spinal column by fusing the twovertebrae and restricting relative movement between the two vertebrae.

As will be discussed below, irregularly shaped inserts or implants 10,11 can be grafts which can be used to fuse together facet joints 1230,1231. Facet joint 1230 can comprise lower portion 1220 of facet joint1230 for vertebra 1200 along with upper portion 1310 of facet joint 1230for vertebra 1300. Facet joint 1231 can comprise lower portion 1221 offacet joint 1231 for vertebra 1200 along with upper portion 1311 offacet joint 1231 for vertebra 1300.

After implantation of irregularly shaped inserts or implants 10 and 11relative movement between vertebrae 1200 and 1300 will be restricted.Additionally, extended direct contact between vertebrae 1200 and 1300will be achieved and maintained. Such direct contact will allowvertebrae 1200 and 1300 to fuse together at the points of direct contactby replacement and/or exchange of bone material.

Where implants are comprised of graft material then such fusion can alsooccur onto and through the implants. It is believed that the greateramount of contact surface area between live bone and a graft implantwill increase and/or speed up the fusion process. Therefore, it isbelieved that an irregularly shaped implant with a large amount ofsurface area is preferred compared to a regularly shaped implant.Examples of regularly shaped implants can be cylinders and/orrectangles.

It is further believed that minimizing the amount of possible relativemovement between the upper and lower vertebrae will accelerate theoverall fusion process. It is believed that allowing relative movementwith respect to the points of contact between the upper and lowervertebrae which are intended to be fused together will interrupt thefusion process at the areas where relative movement is allowed betweenthe points of contact. In such places were relative movement is allowedand the fusion process is interrupted, the fusion process can berequired to begin again as the earlier portion of any bone which wasfused together has now been separated and must be reattached.Additionally, where relative movement occurs multiple times during thefusion process (breaking apart previously fused areas), the ultimatefinal fusion event may be weaker than compared to a fusion process whererelative movement was restricted and/or prevented.

In one embodiment the irregularly shaped implants are shaped to restrictand/or prevent relative movement between upper and lower vertebrae. Inone embodiment the implants can have a plurality of arms which areradially spaced about a longitudinal axis.

It is also preferred to avoid sharp edges in both the implant and thevolume in which the implant is to be inserted to start the fusionprocess. Avoiding sharp edges is preferred because such sharp edges canact as stress concentrators which concentrations of stress can increasethe risk that a mechanical fracture and/or failure occurs in thepatient's vertebrae being fused and/or the implants being used to fusethe patient's vertebra. Accordingly, in one embodiment the implant hasrounded edges in its outer periphery and inner valleys.

In one embodiment the implant is implanted so that it appearssubstantially symmetrical when intersected by the plane of the facetjoint. In one embodiment the implant has a plurality of arms and anequal number of arms fall on one side of the plane of the facet joint asthat falling on the opposite side of the plane of the facet joint.

In one embodiment, after implantation and before fusion, the relativerotation between the implant and the vertebrae being fused ismechanically resisted by forces other than friction. In one embodimentthe implant and the vertebrae being fused have a dovetail relationship.Dovetailing can be a fan-shaped tenon that forms a tight interlockingjoint when fitted into a corresponding mortise. Dovetailing can also bea joint formed by interlocking one or more such tenons and mortises.

In one embodiment an irregularly shaped implant 10 is provided. Theselected size of the implant will be known by those of ordinary skill inthe art based on the size of the vertebra to be fused together includingthe size of the facet joint for such fusion. Such size can be estimatedby x-raying the joints to be fused and/or estimating based on theoverall size of the patient.

In one embodiment implants 10, 11 can include a plurality of arms whichare symmetrically disposed around the longitudinal axis of implants 10,11, and a plane intersecting such longitudinal axis at a right anglecreating a shape which is symmetric about at least one line whichbisects at least one of the arms. Irregularly shaped is intended toexclude implants of a regular shape such as a cylinder and/or arectangle or square. FIG. 32 is a perspective view of irregularly shapedimplant 10 or 11. FIG. 29 is a front view of implant 10 or 11. FIG. 33is an end view of implant 10 or 11.

Implant 10 can comprise first side 20 and second side 30. Each of thesides 20, 30 can be planar surfaces. Implant 10 can include a pluralityof arms 50, 60, 70, 80 which are substantially radially disposed aroundlongitudinal axis 92 which axis passes through center 90 and issubstantially perpendicular to side 20 and side 30. Arms 50, 60, 70, 80can respectively include tips 51, 61, 71, 81. Between arms 50, 60, 70,80 can be valleys 54, 64, 74, 84. Tips 51, 61, 71, 81 and valleys 54,64, 74, 84 are preferably rounded and include no sharp areas (tominimize stress enhancement). In one embodiment tapers 52, 62, 72, 82can be provided so that the size of face 20 is actually smaller than thesize of face 30. Tapering can facilitate insertion of implant 10 into anopening made in a facet joint.

Implant 10 can be constructed such that line 100 is a line of symmetry.Implant 10 can be constructed such that line 120 is a line of symmetry.Arms 50, 60, 70, 80 can be substantially the same size and shape.Alternatively Arms 50, 70 can be substantially the same size and shape;and arms 60, 80 can be substantially the same size and shape, but withthe two sets of arms being of substantially different size and/or shape.For example the length of arm 50 can be longer than the length of arm60; or the width of arm 50 can be smaller than the width of arm 60.

In one embodiment three arms are used. In one embodiment 5, 6, 7, 8, 9,10, 11, or more arms are used. In one embodiment an odd number of armsare used. In one embodiment an even number of arms are used. Althoughnot shown, in one embodiment one or more of the arms can increase inwidth from the valley to its tip. In FIG. 31, implant 21 can be of thesame size and shape of implant 10, 11 but have spaced apart ridges 22that help grip the surgically cut implant opening.

FIGS. 1-5 show guide tool 300. Guide tool 300 can be the tool used bythe surgeon for maintaining the selected position of implantation(location, rotational position, and angular position) for implant 10.Guide tool 300 can comprise first end 310, body 330 and second end 320.On second end 320 can be attached handle 380 which handle can be used toselectively position guide tool 300. Body 330 can include thru opening340 which extends from first end 310 to second end 320. Thru opening 340can include rounded wall 360.

On first end 310 of guide tool 300, can be a plurality of insertionprongs 312, 314. Two insertion prongs 312, 314 are shown, but more canbe used if desired. Insertion prongs 312,314 are intended to dig intospinal column 1100 and fix the location of the ultimate point ofinsertion of implants 10, 11. The location is fixed by prongs 312, 314connecting to the bone of spinal column 1100 (upper and lower vertebrae1200, 1300). The selected Cartesian and rotational location is fixed byinsertion prongs 312, 314. The angular location can be fixed by thesurgeon holding handle 380 such that the angular position between guidetool 300 and the patient is maintained. However, the surgeon has acertain amount of flexibility in modifying the angular position of guidetool 300 (and ultimate angular position of implant 10) by moving guidetool 300 relative to the patient.

FIG. 21 is an anatomical drawing illustrating two vertebrae 1200, 1300.Shown are upper portion 1210, 1211 of a facet joint for vertebrae 1200.The lower portions 1220, 1221 of the facet joints 1230, 1231 forvertebrae 1200 are shown. Upper portions 1310, 1311 for facet joints1230, 1231 are shown as are the upper portions 1310, 1311 of the facetjoints 1230, 1231 of vertebrae 1300.

Insertion prongs 312, 314 assist in holding together upper and lowervertebrae 1200, 1300 during the remaining steps of creation of theopening for implant 10 insertion, and ultimately inserting implant 10.Preferably, at least one insertion prong (e.g., 312) will bite intoupper vertebra 1200 and at least one insertion prong (e.g., 314) willbite into lower vertebra 1300. By this means upper and lower vertebrae1200, 1300 will be fixed relative to each other (e.g., remain at aconstant distance relative to each and not slide relative to each other)during the process of creating the opening for implant 10 for ultimatefusion between upper and lower vertebrae 1200, 1300. As will bedescribed below (see FIG. 2), Line B-B which is in the middle of prongs312, 314 is preferably aligned with plane 1232 of facet joint 1230 (orplane 1233 of facet joint 1231). In this manner upper portions 1310,1311 of facet joints 1230, 1231 for vertebra 1300 can be held close tolower portions 1220, 1221 of facet joints 1230, 1231 for vertebra 1200during the entire cutting and implantation process.

FIGS. 6-19 show bone cutting tool assembly 500. Bone cutting toolassembly 500 can be used to create an opening of proper size andlocation for insertion of implants 10, 11. Bone cutting tool assembly500 can comprise body 505 with first end 510 and second end 520. Onfirst end 510 can be positioned cutter 530 (which can be a replaceablecutting tip and/or allow cutting tips of different sizes and/orconfigurations). On second end 520 can be collar 512. Flange 670 inFIGS. 10-13 determine the depth of penetration of cutting tip 600. Inone embodiment the length of body 530 can be a length substantiallyequal to the length of body 330 of guide tool 300, less the distance640. Collar 512 has arms or flanges 522, 523. The arms or flanges 522,523 are sized and shaped (e.g. curved) to closely conform to handle 380of guide tool 300 (see FIGS. 17, 19). Thus, the radial position of guidetool 300 and its handle 380 determine the radial position of cuttingtool assembly 500 once flanges 522, 523 interlock with handle 380 (seeFIG. 17).

Cutting tool assembly body 505 includes rounded portion 560 of sleeve501 surrounding bore 524 (FIG. 8). On first end 510 can becircumferentially spaced apart slots 540. Cutter 530 (FIGS. 10-13) canbe fitted to body 505 at slots 540. Cutter 530 can be a replaceablecutting tip and/or can be sized and shaped to allow cutting tips ofdifferent sizes. Cutter 530 can include cutting tip 600 having first end610, second end 620 and prongs or arms 652, 656, 660, 664. Between theseprongs or arms can be valleys 653, 657, 661, 665 which respectively arelocated between the arms. These prongs or arms can be sized tocoordinate with implants 10, 11 so that the opening created by theseprongs or arms will fit implants 10, 11. The relative rotationalposition between cutter 530 and cutting tool 500 can be maintained byensuring that the projections 680 of flange 670 interlock with slots540. In FIG. 18, mallet 394 applied flows (arrow 396) to handle 560 whencutting. Cutting tip 600 can have a depth 640 which can determine thedepth of cut for the opening for implant 10 or 11.

Cutter 530 is shown as having an internally threaded area 622 so that itcan be threadably connected to holder 550. Being externally threadedwith threads 570 also allows holder 550 to be detachably connected to acoupon removal tool. Holder 550 has handle 560 and shaft 580. Cutter 530can include first end 610 and second end 620. Cutting tip 600 can betapered, which tapering can be sized to match any tapering of implant10, 11. Alternatively, cutting tip 600 need not be tapered even whereimplant 10, 11 is not tapered.

In one embodiment, a plurality of cutting tips 600, 600′, 600″, 600′″,etc. of cutters 530 can be included which can be detachably connectableto cutting tool body 505 and holder 550 at shaft 580. Such plurality ofcutting tips can be of different sizes and configuration if desired tomatch implants 10, 10′, 10″, 10′″, 10″″, etc. of different sizes andconfigurations. Additionally, a plurality of cutting tips which aredetachably connectable to cutting tool 500 (even if of the same size andconfiguration) so that such cutting tips can be replaced after beingused for a patient with an implantation surgery. Replacing only thecutting tips is believed to reduce the overall cost as no additionalcutting tool 500 need be purchased. However, the various tools used inthe implantation surgery should be cleaned and disinfected before andafter any implantation surgery.

FIGS. 22-37 show implant holder and insertion tool 700. Tool 700 hasfirst end 710, second end 720, and body 730. Body 730 can includeopening or bore 740. Accordingly, once the position (location/Cartesian,rotational, and angular) of implantation is selected using prongs 312,314 of guide tool body 330 this position will be maintained with respectto implant insertion tool 700. Body 730 can have a length which may beequal to or longer than the length of body 330 of guide tool 300.

On first end 710 can be an opening 800 with a depth 810 for receivingimplant 10 or 11. Opening 800 can include prongs or arms 852, 856, 860,864. Between these prongs or arms can be valleys (not labeled forclarity). These prongs or arms can be sized to coordinate with the shapeor periphery of implant 10 or 11 (see FIGS. 29, 33) so that the openinghaving these prongs or arms will accept implant 10. It is preferred thatthe depth 810 of opening 800 be less than the depth or height 40 ofimplant 10 or 11 so that implant 10 or 11 will at least partially extendfrom first end 710. At least partially extending from first end 710facilitates insertion of implant 10 into the opening made by cuttingtool 500 in spinal column 1100.

Insertion tool 700 can include a plurality of slots or cutouts 712, eachhaving a depth 714. These cutouts 712 facilitate the insertion and/orremoval of implant 10 from opening 800 on first end 710. These cutouts712 create a plurality of arms which act as cantilever springs so thatthe arms can relatively easily expand and accept implant 10 into opening800. Additionally, these arms allow implant 10 to be relatively easilyremoved from insertion tool 700.

Insertion tool 700 can include an open ended bore or thru opening 740extending from first end 710 to second end 720. Thru opening 740 can becylindrical in shape. Thru area 740 can be sized to accept shaft or body930 of impacting tool 900. Impacting tool 900 can include first end 910,second end 920, and body 930. Body 930 can have a length which may beequal to or longer than the length of body 330 of guide tool 300. Onsecond end 920 can be attached handle 922.

For the method of the present invention, the goal is to implant anirregularly shaped implant 10 or 11 into a facet joint 1230 or 1231between upper and lower vertebra 1200, 1300 of spinal column 1100 in aposition and orientation (Cartesian location, rotational, and angular)selected by the surgeon. Generally, the method and apparatus includes anirregularly shaped implant 10 which is of a graft material and themechanism to insert this implant into a patient's facet joint which willfacilitate fusion between the upper and lower vertebrae of the facetjoint while the implant resists relative movement between the upper andlower vertebrae of the facet joint.

Generally, the steps include (a) selecting an irregularly shapedimplant; (b) selecting a position of implantation; (c) selecting anorientation for implantation; (d) creating an opening for implantationhaving such position and/or orientation; and (d) inserting the implantinto the opening having such position and/or orientation. In oneembodiment, the orientation includes a rotational orientation. In oneembodiment the orientation includes an angular orientation. In oneembodiment the implant includes a plurality of prongs or arms.

FIGS. 21 and 37 are diagrams schematically showing two irregularlyshaped implants 10, 11 implanted in the facet joints 1230, 1231 ofvertebrae 1200, 1300. The prongs or arms of these implants 10, 11 areshown only in schematic form. FIG. 37 is a cross section with the armsor prongs of implants 10, 11 shown only in schematic form. Such implants10, 11 can either individually and/or in combination resist relativemovement of vertebrae 1200, 1300 in various directions. Relativerotational movement between vertebrae 1200, 1300 can be resisted by thearms or prongs of the implants 10, 11. Additionally, relative angularmovement (such as rotation along a line included in facet plane 1232 offacet joint 1230 where such line is perpendicular to the longitudinalaxis of implant 10) can be resisted by the prongs or arms of implant 10where these prongs or arms interlock with the opening created in thefacet joint 1230 for implantation. Similarly, angular rotation can beresisted by implant 11 and facet joint 1231. Such resistance to relativemovement is believed to shorten the overall fusion process betweenvertebrae 1200, 1300 by minimizing situations where relative movementcould occur which could cause the fusion (e.g., grafting) process to beinterrupted and/or slowed.

On first end 310 of guide tool 300, can be a plurality of insertionprongs 312, 314 which are intended to dig into spinal column 1100preferably above and below a facet joint 1230 or 1231. This fixes thelocation of the ultimate point of insertion of implant 10 or 11 in facetjoint 1230 or 1231. The location fixed by prongs 312,314 detachablyattaches to the bone of spinal column 1100 (in both the upper and lowervertebrae 1200, 1300). The selected Cartesian and rotational locationremain fixed by insertion prongs 312,314 into the bone of upper andlower vertebrae 1200, 1300.

The angular location can be fixed by the surgeon holding handle 380 suchthat the angular position between guide tool 300 and the patient ismaintained. However, the surgeon has a certain amount of flexibility inchanging the angular position of guide tool 300 (and ultimate angularposition of implant 10 or 11) by moving guide tool 300 relative to thepatient.

Insertion prongs 312,314 also assist in holding together upper and lowervertebrae 1200, 1300 during the remaining steps of creating of theopening for implant 10, 11 insertion, and ultimately inserting implant10 or 11. Preferably, at least one insertion prong (e.g., 312) will biteinto upper vertebra 1200 and at least one insertion prong (e.g., 314)will bite into lower vertebra 1300. By this means upper and lowervertebrae 1200, 1300 will be fixed relative to each other (e.g., remainat a constant distance relative to each and not slide relative to eachother) during the process of creating the opening for implant 10 forultimate fusion between upper and lower vertebrae 1200, 1300. As will bedescribed below Line B-B which is in the middle of prongs 312, 314 ispreferably aligned with plane 1232 of facet joint 1230. In this mannerupper portion 1310 of facet joint 1230 for vertebra 1300 can be heldclose to lower portion 1220 of facet joint 1230 for vertebra 1200 duringthe entire implantation process.

The next step will be creating the properly sized opening for implant 10which can be made using cutting tool 500 with cutting tip 600. FIG. 18is a side view of a cutting tool 530 with cutting tip 600 being insertedinto the guide tool 300. To cause the opening for implant 10, 11 to bemade cutting tip 600 is forced into the bone of spinal column 1100through an application of force on handle 560. FIG. 19 is a side view ofthe cutting tip 600 completely inserted into the guide tool 300 and nowhaving cut into the facet joint (not shown for clarity) via the cuttingtip 600. Flanges 522, 523 are in contact with handle 380 of guide tool300. Cutting tip 600 is extending out of first end 310 of guide tool 300a distance 640. Distance 640 is the depth of opening made for implant10. At this same time prongs 312, 314 remain fixed in the bone of spinalcolumn 1100 to allow cutting tip 600 to make the proper sized opening.

After the opening for implant 10 has been made, cutting tool 500 can beremoved by pulling on handle 560 and sliding cutting tool 500 out ofguide tool 300. In some cases plug or coupon 371 will come out of thespine of patient along with cutting tool 500 such as by friction betweencutting tool 500 and plug or coupon 371. However, plug or coupon 371will not always come out with cutting tool and an additional step ofplug or coupon removal will be required. Various embodiments can be usedto remove the cut plug or coupon 371 as will be described below. Forexample, the grabbing plug or coupon removal tool assembly of FIGS.38-40 could be used (which procedure is described below). As anotherexample the threaded and wedging plug or coupon removal tool assembly ofFIGS. 53-58 could be used (which procedure is also described below).

The next step in the process is inserting implant 10 or 11 into thesurgically cut opening. Insertion of implant 10 or 11 can be greatlyfacilitated where the position of implant 10 or 11 (to be implanted) iscoordinated (Cartesian location, rotational, and angular) with theposition of opening for implant 10. Accordingly, in the next step animplant insertion tool 700 is used which can so coordinate the insertionof implant 10 into previously made opening.

FIGS. 22-37 show views of implant insertion tool 700 along withirregularly shaped implant 10 or 11. To cause implant 10 or 11 to beinserted into the opening for implant 10 or 11, insertion tool 700 isslid through opening 340 of guide tool 300. At this same time prongs312,314 remain fixed in the bone of spinal column 1100 to allowinsertion of implant 10 at the proper orientation relative to theopening for implant. Arrows 392 and 390 schematically indicate thatrotational and angular remain fixed. FIG. 36 is a side view of theimplant insertion tool 700 with irregularly shaped implant 10 completelyinserted into the guide tool 300 so that the implant 10 is at leastpartially inserted into the opening previously cut into the facet joint(the facet joint not being shown for clarity) by the cutting tool 500.At least part of implant 10 should extend from first end 710 ofinsertion tool 700 to facilitate insertion of implant 10 into opening.The surgeon is expected to feel some resistance when inserting thepartially extending portion of implant 10 or 11. However, the surgeon isexpected to feel this portion slide into the opening surgically cut.During this process of inserting the surgeon can moved back and forthsecond end 720 of insertion tool 700 to actually cause implant 10 or 11to enter the surgically cut opening. First end 710 will stop moving onceit contacts the bony area around the opening for implant 10. During thisprocess prongs 312 and 314 hold together the upper and lower vertebraeand maintain the shape and position of the opening for implant.

Once implant 10 has been at least partially inserted into the opening,implant 10 should be ejected from implant insertion tool 700 and morefully (preferably fully) inserted into the opening for implant. Ejectingimplant 10 or 11 from insertion tool 700 and more fully insertingimplant 10 or 11 into opening for implant 10 can be facilitated byimpaction tool 900 which can slide through insertion tool's 700 thruopening 740 and push on implant 10 causing it to be ejected frominsertion tool 700 and being more fully inserted into the opening forimplant 10. FIG. 36 is a side view of an implant impaction tool 900being inserted into the implant insertion tool 700 (insertion beingschematically indicated by arrow 400) which tool 700 itself waspreviously inserted into guide tool 300.

The above described process can be repeated step by step forimplantation of irregularly shaped implant 10 or 11 for fixation andfusion of facet joint 1230, 1231.

Irregularly shaped implant 10 can be an autograft, cadaveric allograftor FDA approved synthetic pre-made, pre-shaped cortical bone insert,implant, or graft. The procedure is envisioned to require only oneimplant per facet joint and two per level. Permanent fixation occurswhen bone in-growth occurs into the joint itself and into the implantover time.

FIGS. 38-51 illustrate a tool 370 that can be used to remove bone tissuethat has been cut with cutting tip 600 of cutter 530. If the cut bone371 does not lodge itself in cutting tip 600, it must be removed. Tool370 attaches to holder 550 at threaded end 570 (see FIGS. 38-39, 45-46).As a surgeon rotates handle 560 (see arrow 382, FIG. 43) of holder 550,a plurality of arms 372 of tool 370 converse on the cut bone 371 andgrip it (see arrows 381, FIGS. 43,49). Arms 372 are separated bylongitudinal slots 373. In order to set the tool 370 in its properposition to remove cut bone 371, a gauge 374 is employed. Gauge 374 hasa cylindrical handle 376 and an implant shaped projection thatcorresponds generally in size and shape to the surgically cut bone to beremoved. In FIGS. 42-44, a surgeon sets the position of arms 372 byplacing the arms in contact with projection 375, rotating handle 550until the arms snugly grab the implant shaped projection 375. Thesurgeon then reverses the rotation of handle 550 to release theprojection 375 of gauge 374. The handle might be turned a half turn or aturn for example to release the projection 375 of gauge 374.

Tool 370 has an internally threaded socket 377 that is engaged with thethreads 570 of holder 550. Tool 370 has a similar size and shape tocutter 530, providing flange 378 with projections 379 that fit the slots540 of cutter sleeve 501 (see FIGS. 38-40).

FIG. 45 shows a rotation of handle 560 (arrow 383) to grip the cut bone371. After securing the cut bone 371, it is removed from spine 1100 andguide tool 300. Rotation of handle 560 (see arrow 384 in FIG. 46)expands arms 372 and the cut bone 371 is discharged.

FIGS. 53-68 show an alternate coupon removal assembly, method, andapparatus. In FIGS. 59, 60, 61 and 63, the coupon removal assembly isdesignated generally by the numeral 1400. The coupon removal assembly orplug removal assembly of FIGS. 53-68 is an alternate to the plugremoving tool of FIG. 38. As with the plug removing tool of FIG. 38, thecoupon removal assembly or plug removing tool 1400 (such as shown inFIGS. 53-68) could be used as part of the method and apparatus of thepresent invention such as in combination with the guide tool 300 duringa surgical procedure that removes a coupon or plug or bone debris 371and replaces that coupon or plug or debris 371 with an insert or implant10, 11, 21. The coupon removal assembly 1400 can thus be used with anyof the embodiments, in place of the grabbing tip plug removal tool ofFIGS. 38-39.

Coupon removal assembly or plug removal tool 1400 employs a cutter 1401.The cutter 1401 includes a conically shaped coupler 1402 having aninternally threaded bore 1403. The coupler 1402 can provide afrustoconically shaped outer surface 1404. The internally threaded bore1403 is sized and shaped to form a connection with the external threads1413 of holder 1411 as shown in FIGS. 59, 62 and 64-65. Coupon removalassembly or plug removing tool 1400 can employ the cutter sleeve 501.Sleeve 501 was also a part of the removal tool of FIGS. 38-39. Cuttersleeve 501 thus provides body 505 having first end 510 and a collar 512at second end 520. Arms or flanges 522, 523 are spaced from body 505,and are attached to collar 512 as shown. The cutter sleeve 501 providesa longitudinally extended open ended bore 524 and slots 540 that arereceptive of projections 680 of flange 670. The end 610, flange 670,projections 680 of cutter 1401 can thus be the same as for the cutter530 of the plug removal tool shown in FIGS. 38-39 and described inrelated text.

Cutter 1401 can thus be similar in shape and configuration to the cutter530 of FIG. 13. The cutter 1401 however provides conically shapedcoupler 1402, internally threaded bore 1403, frustoconical surface 1404for enabling connection to holder 1411. The internally threaded bore1403 is configured to receive and to connect with the external threads1413 of holder 1411 (see FIGS. 57, 59, 62-64).

Holder 1411 includes one end portion having handle 1412 to which isattached shaft 1415. The other end portion of holder 1411 providesexternal threads 1413 on shaft 1415. Shaft 1415 is an elongated shaftthat can be tapered or frustoconically shaped (see FIGS. 57, 59). Shaft1415 provides an open ended bore 1414 as shown in FIG. 57.

Handle 1405 (FIGS. 54, 59, 63) fits end portion 520 of cutter sleeve501. Handle 1405 provides a socket 1406 having a smaller diameteropening 1407 and a larger diameter opening 1408 that is sized and shapedto fit end 520 of cutter sleeve 501. Handle 1405 provides appendages1409, 1410 that can be arranged approximately one hundred eighty (180)degrees apart.

Removal tool 1416 provides a handle 1417 at one end portion and a shaft1420 with a tip 1419 at its other end portion. An externally threadedsection is provided at 1418 next to tip 1419. Shaft 1420 extends betweentip 1419 and handle 1417. Shaft 1420 is sized and shaped to fit insideof bore 1414 of holder 1411 as shown in FIGS. 59, 60, 61, 62 and 63.Arrow 1421 in FIG. 61 illustrates that handle 1417 and thus removal tool1416 can be rotated such as when engaging and imbedding the externallythreaded section 1418 into a coupon or plug of bone 371 to be removedfrom a patient's spine 1100 at a selected facet joint.

In order to remove a coupon or plug of bone 371 and thus provide asurgically cut opening or cavity 1424, a surgeon places guide tool 300next to the patient's spine 1100 next to a selected facet joint as shownin FIG. 63 and as was shown and described with respect to the preferredembodiment of FIGS. 1-52. As shown in FIGS. 59-64, cutter sleeve 501 isplaced inside of guide tool 300. Handle 1405 is placed upon end portion520 of cutter sleeve 501. Shaft 1415 of handle 1412 is then insertedthrough smaller diameter opening 1407 of handle 1405 and then into thebore 540 of cutter sleeve 501. External threads 1413 of holder 1411engage the internal threads or internally threaded bore 1403 of cutter1401 (see FIGS. 59, 62 and 64). The cutter 1401 end 610 is then driveninto the patient's spine 1100 in order to form a surgically cut openingor cavity 1424 (see FIGS. 63-65). Handle 1417 of removal tool 1416 isthen rotated so that the threads 1418 engage the cut bone 371 to beremoved. A surgeon then lifts the holder 1411 and removal tool 1416upwardly by grasping the appendages 1409, 1410 of handle 1405 whilesupporting guide tool 300 using handle 380 as shown in FIG. 63.

By inserting the tip 1419 and external threads 1418 at the lower end ofshaft 1420 of removal tool 1416 into the spine 1100, the cut bone orcoupon or plug 371 expands slightly and thus engage the first end 610 ofthe cutter 1401 to create a tight, a snug or an interference fit. Forthe cutter 1401, the first end 610 can be sized and shaped as the cutter530 of FIGS. 10-13. Arrow 1422 illustrates this removal of the cuttersleeve 501, handle 1405, holder 1411, and removal tool 1416 togetherwith the cut bone/coupon/plug 371. In FIG. 65, arrow 1423 schematicallyillustrates the removal of the cut bone/coupon/plug 371 leavingsurgically cut opening or cavity 1424 in spine 1100.

In FIGS. 66-68, a bone removal tool 1425 is shown, which similar to thebone removal tool of FIGS. 38-40. Removal tool 1425 is provided withbarbs 1429 on the inner surface of arms 1426 as shown in FIGS. 66-68. Aswith the bone removal tool 370, the bone removal tool 1425 provides arms1426, slots 1427 separating the arms, and an internally threaded socket1428. The use of the barbs 1429 (which are upwardly facing) helps resistslippage during removal of the coupon, plug, bone debris or or cut bone371.

FIG. 69 is a side view of a facet joint locator 1430 having at least onelongitudinal positioning line 1439. In one embodiment two longitudinalpositioning lines 1439 and 1439′ can be provided on opposite sides ofthe facet joint locator 1430 and in the same plane that containsflange/blade 1433. FIG. 70 is a sectional view of the facet jointlocator 1430 taken along the lines 70-70 of FIG. 69. FIG. 71 is aperspective view of the facet joint locator 1430.

FIGS. 69-71 show facet joint locator 1430. The facet joint locator 1430provides a proximal end portion 1431 and a distal end portion 1432.Flange 1433 is mounted at distal end portion 1432. The flange 1433provides a tip 1434. The flange 1433 provides a tip 1434 and surfaces1435, 1436. The surfaces 1435, 1436 can be planar surfaces that aregenerally parallel.

Facet joint locator 1430 has a frustoconical section 1437 and agenerally cylindrically shaped section 1438. Flange 1433 attaches tofrustoconical section 1437 as shown in FIGS. 69-71. An alignment mark1439 (or multiple alignment marks 1439) can be provided on facet jointlocator 1430 such as on the cylindrical section 1438 as shown in FIG.71. The alignment mark or marks 1439 fall in a plane that is generallyco-planar with one of the surfaces 1435, 1436.

FIG. 72 is a perspective view of a step in the method and apparatus ofone embodiment where the surgeon uses facet joint locator 1430 to locatethe facet joint in which an opening is to be made for insert, implant,plug, or graft 10,11,21. FIG. 73 is a close up perspective view of thefacet joint locator 1430 shown inside the facet joint. FIG. 74 is a sideview of guide tool 300 being positioned over the facet joint locator1430 and contacting the spine 1200 of a person over the facet joint(points 314 are shown digging into the spine).

FIG. 75 is a partial perspective view of the guide tool 300 and facetjoint locator 1430 where the guide tool 300 has a positioning mark 1439which is lined up with the positioning mark 1440 in the handle 380 whichalignment orients subsequent steps (cutting of opening 1424, removal ofcoupon or plug 371, and insertion of insert, implant, plug, or graft10,11,21 into opening 1424) with respect to the orientation of theopening or bore 1424 in the facet joint to be fused.

In FIGS. 72 and 73, a surgeon places the facet joint locator 1430 flange1433 in a position that contacts the spine 1200 to locate the facetjoint 1230 or 1231. FIG. 73 is a close-up perspective view of the facetjoint locator 1430 shown with the flange or blade 1433 inside the facetjoint 1230 or 1231. In FIG. 74, a side view of the guide tool 300 isshown being positioned over the facet joint locator 1430 and contactingthe spine 1200 next to the facet joint. FIG. 75 shows that the guidetool 300 can be provided with an alignment mark 1440. The guide toolpositioning mark 1440 is lined up with the alignment mark 1439 of thefacet joint locator 1430. In FIG. 75, the guide tool 300 has beenproperly aligned with the alignment mark 1439 of the facet joint locator1430 and thus is properly aligned with the flange or blade 1433 of thefacet joint locator 1430 which engages a facet joint 1230 or 1231.

FIG. 76 is a perspective view of an insert, implant, plug, or graft10,11,21 being placed in an alternative embodiment of the insertion tip1500 of the method and apparatus where a portion of the insert, implant,plug, or graft 10,11,21 protrudes or extends outside of the insertiontip 1500. In this embodiment about two thirds protrudes from theinsertion tip 1500.

FIG. 77 is a sectional side view of the insertion tip 1500 placing theinsert, implant, plug, or graft 10,11,21 into the opening or bore 1424previously made around the facet joint (1230 or 1231) of a person'sspine 1200 where the orientation of the insert, implant, plug, or graft10,11,21 is maintained with the opening or bore 1424 based on theorientation of the original facet joint locator 1430 shown in FIG. 75.

FIG. 76 is a perspective view of an insert, implant or plug such asimplant 10, 11, 21 being attached to an alternative insertion tip 1500.Insertion tip 1500 can have first end 1520 and second end 1530. Firstend 1520 can have a threaded internal bore which is connected withopening 1540 of second end 1530. Tip 1500 can have an externally taperedsection 1510 and include a plurality of slots on the second end 1530.Tip 1500 can also include a plurality of alignment projections or tips1560 which cooperate with the plurality of slots 540 of tool 500 inorder to orient the alignment of opening 1540 with the cut or opening1424 made previously in the spine 1200 about the facet joint.

Opening 1540 can correspond to the respective shape of insert, implant,or plug 10,11,21 and include a shoulder 1550 restricting thelongitudinal depth to which insert, implant, or plug 10,11,21 can beinserted into opening 1540. Tip 1500 can be properly aligned withrespect to tool 500. Because tool 500 is aligned with respect to guidetool 300 (by arms 522 and 523 limiting movement with respect to handle380 of guide tool 300), the opening 1550 (and implant, insert, or plug10,11,21) will be aligned with opening 1424 in spine 1200.

If the shape of the insert, implant, or plug 10,11,21 is symmetricalthen the relative positioning of the alignment projections or tips 1560are not that important as falling within any slot 540 will align theshape of opening 1540 with the cut or opening 1424 in spine 1200. If theshape of insert, implant, or plug 10,11,21 is not symmetrical then theplurality of slots 540 can be made to respectively fit only a certainnumber of the plurality of alignment tips or projections 1560. Forexample, these two sets (540 and 1560) can be numbered respectively toprovide the proper alignment. Alternatively, they can be differentshapes or sizes to force a particular alignment between tip 1500 andtool 500. Similarly, the alignment of cutting tip 610 (with itsalignment prongs or tips 680) and grabbing tip 1425 (with its pluralityof alignment prongs or tips) can be obtained. In this manner, from theoriginal cutting of the opening 1424, removal of the coupon or plug 371,and insertion of the insert, implant, or plug 10,11,21 the properorientation can be made with respect to the facet joint, opening to bemade, and insert, implant, or plug to be inserted for fusion of thefacet joint.

Alternative insertion tip 1500 allows the surgeon to control the amountof force the tip 1500 places on insert, implant, or plug 10,11,21 whilebeing held in opening 1540. FIG. 77 shows tip 1500 threadably connectedto holder 1411. Tapered section 1510 of tip 1500 is in contact withinternally tapered portion of tool 500. Plurality of alignment tips orprongs 1560 are shown located in alignment slots 540 of tool 500. Ifhandle 1411 is turned in the direction of arrow 1514 tip 1500 will movein the opposite direction of arrow 1516 which will cause the second end1530 to be squeezed inwardly as schematically indicated by arrows 1512in FIG. 76. Handle 1410 will rest on second end 520 of tool 500 (seeFIG. 59 showing connection to cutting tip 610 but connection withinsertion tip 1500 will be substantially similar). As squeezed in thedirection of arrows 1512 greater grabbing force is placed on insert,implant, or plug 10,11,21 to prevent it from falling out of tip 1500 andalso maintain proper longitudinal alignment between insert, implant, orplug and the centerline of opening 1424 from the time tool 500 (with tip1500 and insert, implant, or plug 10,11,21) is inserted into guide tool300 and insert, implant, or plug is inserted into opening 1424.

Insert, implant, or plug 10,11,21 protrudes from tip 300 because it isbelieved that a protruding condition facilitates placement of insert,implant, or plug into opening 1424. Shoulder 1560 limits or restrictsthe amount of insertion of insert, implant, or plug 10,11,21. Indifferent embodiments the protrusion is about 1/16, ⅛, 1/7, ⅙, ⅕, ¼, ⅓,½, ⅔, or ¾ of the insert's, implant's, or plug's length. In variousembodiments the protrusion is within a range of between about any two ofthe above specified amounts.

In FIGS. 77 and 78, insertion tip 1500 could thus provide an internallythreaded socket 1521 having internal threads that are sized and shapedto engage the external threads 1413 of holder 1411. In FIGS. 77 and 78,there is provided a sectional side view of the insertion tip 1500placing the insert, implant or plug 10, 11, 21 into the surgicallyformed opening 1424 in facet joint 1230 or 1231 that was formedpreviously such as be using cutter 1401). A surgically formed opening1424 can be cut or stamped in the patient's spine 1200 at the facetjoint as aforedescribed. The orientation of the insert, implant or plug10, 11, 21 is maintained based upon the orientation of the originalfacet joint locator tool 1430. In FIG. 78, the insertion rod orimpaction tool 900 of FIG. 23 is used to fully push the insert, implant,plug or graft 10, 11, 21 into the surgically formed opening 1424 at thefacet joint 1230 or 1231.

Surgical Method

In one embodiment the method and apparatus includes an allograftdesigned to fuse the facet joint. The facet joint can be identifiedeither via an open approach (traditional laminectomy exposure) or via apercutaneous approach with stab incisions on either side of the spinousprocess at the appropriate level. In this approach you will need to usefluoroscopy to localize the appropriate joint and location.

An implant opening can be made via a bone stamper, cutter (or die) bysetting the cutter or (die) on the dorsum of the facet joint and gentlyimpacting until being flush on the joint surface. The position of theopening (Cartesian and/or rotational) can be determined by a positioningselector and maintained via a guide in which all tools are positionallydetermined. The cutter or stamper can be withdrawn after partial closureof the terminus of the stamper. The joint material (cartilage and boneprimarily) with be withdrawn as this device exits the joint.

Stamping an opening is advantageous to other devices which drill or“grind” the tissue and/or bone. This can have adverse effects onarthrodesis. The cutter or stamper can be slightly undersized allowingfor an ultimate press fit of a graft into the implant opening made bythe stamper. The implant can then be placed into the guide tool whichcorrectly positions the implant for insertion into the opening. Theimplant can then be impacted gently into the opening created in thefacet joint until it seats flush with the opening. All tools can then bewithdrawn and the patient closed.

In one embodiment the irregularly shaped implant can lock the two“hands” (or upper and lower halves) of the facet joint together. Thislocking will then lead to accelerated fusion of the joint and decreasein the generation of pain.

The following is a list of reference numerals:

LIST FOR REFERENCE NUMERALS

(Part No.) (Description) Reference Numeral Description 10 insert/implant11 insert/implant 20 first side 21 implant 22 ridge 30 second side 40depth or height 42 protruding section 50 prong or arm 51 tip 52 taperfrom first side to second side 54 valley between prongs or arms 60 prongor arm 61 tip 62 taper from first side to second side 64 valley betweenprongs or arms 70 prong or arm 71 tip 72 taper from first side to secondside 74 valley between prongs or arms 80 prong or arm 81 tip 82 taperfrom first side to second side 84 valley between prongs or arms 90center 92 longitudinal axis 100 line 120 line 300 guide tool 310 firstend 312 insertion prong 314 insertion prong 320 second end 330 body 340thru opening 360 rounded wall of thru opening 370 bone removal tool 371cut bone/coupon/plug 372 arm 373 slot 374 gauge 375 implant shapedprojection 376 cylindrical handle 377 internally threaded socket 378flange 379 projection 380 handle 381 arrow 382 arrow 383 arrow 384 arrow385 surgically cut opening/cavity 390 arrows 392 arrows 394 mallet 396arrow 500 bone cutter/bone cutting tool assembly 501 cutter sleeve 505body 510 first end 512 collar 520 second end 522 arm/flange 523arm/flange 524 bore 530 cutter 540 slot 550 holder 560 handle 570threads 580 shaft 600 cutting tip 610 first end 620 second end 622threaded area 640 depth of cutting tip 652 prong or arm 653 valleybetween prongs or arms 656 prong or arm 657 valley between prongs orarms 660 prong or arm 661 valley between prongs or arms 664 prong or arm665 valley between prongs or arms 670 flange 680 projection 700 tool forholding and inserting implant or insert 710 first end 712 plurality ofcutouts/slots 714 depth of the plurality of cutouts 720 second end 730body 740 thru opening in body/bore 800 opening for receiving implant orinsert 810 depth of opening 852 prong or arm 856 prong or arm 860 prongor arm 864 prong or arm 900 impaction tool 910 first end 920 second end922 handle 930 body 1100 spinal column 1200 vertebrae 1210 upper portionof facet joint for vertebra 1211 upper portion of facet joint forvertebra 1220 lower portion of facet joint for vertebra 1221 lowerportion of facet joint for vertebra 1230 facet joint 1231 facet joint1232 plane of facet joint 1233 plane of facet joint 1300 vertebra 1310upper portion of facet joint for vertebra 1311 upper portion of facetjoint for vertebra 1320 lower portion of facet joint for vertebra 1321lower portion of facet joint for vertebra 1400 coupon removal assembly1401 cutter 1402 conically shaped coupler 1403 internally threaded bore1404 frustoconical surface 1405 handle 1406 socket 1407 smaller diameteropening 1408 larger diameter opening 1409 appendage 1410 appendage 1411holder 1412 handle 1413 external threads 1414 bore 1415 shaft 1416removal tool 1417 handle 1418 externally threaded section 1419 tip 1420shaft 1421 arrow 1422 arrow 1423 arrow 1424 surgically cutopening/cavity 1425 bone removal tool 1426 arm 1427 slot 1428 internallythreaded socket 1429 barb 1430 positioning selector tool (e.g., facetjoint locator) 1431 proximal end 1432 distal end 1433 flange/blade 1434tip 1435 surface 1436 surface 1437 frustoconical section 1438cylindrical section 1439 alignment mark 1440 alignment mark 1500insertion tip 1510 tapered portion 1512 arrows 1514 arrow 1520 first end1521 longitudinal bore or opening 1522 threads 1530 second end 1540opening 1550 shoulder 1560 plurality of alignment tips

All measurements disclosed herein are at standard temperature andpressure, at sea level on Earth, unless indicated otherwise. Allmaterials used or intended to be used in a human being arebiocompatible, unless indicated otherwise.

It will be understood that each of the elements described above, or twoor more together may also find a useful application in other types ofmethods differing from the type described above. Without furtheranalysis, the foregoing will so fully reveal the gist of the presentinvention that others can, by applying current knowledge, readily adaptit for various applications without omitting features that, from thestandpoint of prior art, fairly constitute essential characteristics ofthe generic or specific aspects of this invention set forth in theappended claims. The foregoing embodiments are presented by way ofexample only; the scope of the present invention is to be limited onlyby the following claims.

The invention claimed is:
 1. A method of mounting an implant in a facetjoint C1-C2 and L5-S1, the method comprising the steps of: (a) cuttingan arthroscopic type portal in the tissue of a patient outside adiseased or damaged facet joint; (b) using a positioning selection toolto select an orientation of a plug to be implanted, the selectedorientation including a plurality of prongs defining an orientation ofthe plug to be implanted; (c) placing an implantation guide in operativeconnection with the positioning selection tool; (d) while maintaining atleast two distinct prongs of the selected orientation removing thepositioning selection tool from operative connection with theimplantation guide; (e) placing a cutting tool in operative connectionwith the implantation guide, and using operative connection between thecutting tool and implantation guide to form a shaped hole between twoopposed bones forming the facet joint, the shaped hole having at leastthe two distinct prongs of orientation specified in step “d”; and (f)inserting a preshaped plug into the hole, the plug having a shapesubstantially the same as the hole.
 2. The method of claim 1, wherein instep “f” the plug comprises: (i) a substantially solid body having alongitudinal axis; (ii) a plurality of opposed arms, the arms beingsymmetrically disposed around the longitudinal axis; and (iii) the bodybeing formed from a material selected from the group consisting ofsynthetic cortical bone, a harvested synthetic cortical and compactediliac crest graft and a cadaveric allograft.
 3. The method of claim 2,wherein there are four arms.
 4. The method of claim 3, wherein the fourarms form an “X”.
 5. The method of claim 2, wherein the arms includetips which are rounded.
 6. The method of claim 5, wherein between eachpair of arms is a valley which valley is rounded.
 7. The method of claim2 wherein the body is formed from synthetic cortical bone.
 8. The methodof claim 2 wherein the body is formed from a harvested and compactediliac crest graft.
 9. The method of claim 2 wherein the body is formedfrom a cadaveric allograft.